How to make modifiers not auto-apply or update live while changing parameters?
Set modifier on a simple object and then transfer it to a more complex one

Use an "host" object to set up your modifier with the wanted
   parameters (e.g. a simple plane/a cube/a vertex..).

Once the modifier is added, switch its 3D vieport visibility off to prevent calculations.

Once satisfied with the settings, select both objects, make the "host" object the active object and then Link the modifier to the other by pressing Ctrl+L and choosing Modifiers from the pop up menu.



The modifier will be transferred with all his settings, even its "non visbility", to the selected objects, so you'll just have to apply it and wait for the end of the calculations.